This invention relates to a compact food processing appliance containing an invertible/reversible rotary food processing tool and more particularly, to such an applicance having an overhead releasable elevating spindle drive eliminating the need for mounting the rotary tool on active bearing means which at high speeds can overheat.
This invention relates to an improvement in apparatus disclosed and claimed in application Ser. No. 945,490 filed Dec. 23, 1986, now U.S. Pat. No. 4,723,719, and entitled "INVERTABLE/REVERSIBLE TOOL FOR USE IN A ROTARY FOOD PROCESSING APPLIANCE" by the present inventor. That application has a rotary food processing tool with blades extending outwardly therefrom which performed certain types of food processing operations in a first position and other types of food processing operations in an upside-down position.
The appliance in said prior patent application includes motor-driven drive means extending into the bowl for rotating the tool about a vertical axis in the bowl. The processing tool advantageously has an elongated upright hub adapted to be rotated about a vertical axis by the drive means for performing predetermined food processing operations in a first position and other predetermined food processing operations when the tool is inverted for rotation in a second upside-down position. The elongated upright hub has first and second coupling means on opposite ends thereof each of which is adapted to engage the drive means in driven relationship for rotating the upright hub about the vertical axis in a first direction when the first coupling means is engaged and in a second direction when the second coupling means is engaged with the drive means.
In that appliance the invertible/reversible tool is mounted in the bowl on an upstanding rotatable guide shaft mounted on the bottom of the bowl for rotation about a vertical axis by means of a sealed bearing unit which is anchored to the bottom of the bowl. Accordingly, this rotatable guide shaft rotates with the rotary tool whenever the tool is being rotated by the drive means. Thus, the sealed bearing unit is driven at relatively high speeds, and because of its compact size has a tendency to overheat. This compact sealed bearing unit cannot be operated continuously for long periods of time because of the tendency to overheat. Although this limit on continuous operation is not a problem when the appliance is used properly, it would be desirable to eliminate this sealed bearing unit to insure longer, more reliable performance by the appliance and to eliminate the costs associated with such a sealed bearing unit.